I. Field of the Invention
The present invention relates in general to rocker arms for internal combustion engines and more particularly to an all ceramic rocker arm for an internal combustion engine.
II. Description of the Prior Art
An all ceramic rocker arm, i.e., a rocker arm entirely made of ceramics has been proposed for use in an automotive engine for the reason of a light weight, excellent wear resistivity and high rigidity, as disclosed in Japanese Provisional Patent Publication No. 62-206206.
The all ceramic rocker arm however has a possibility of being broken when subjected to such a large impact that is caused at the overspeed of the engine. When the rocker arm is broken, small broken pieces are scattered violently to damage the adjacent parts, and in some case the broken pieces are mixed with lubrication oil and intrude into the engine proper through the lubrication system to cause breakage or sudden stoppage of the engine proper, leading to a serious accident.